The present invention relates to an expansible plug
More particularly, it relates to an expansible plug which has a closed shank section composed of two shank halves and an expanding element for expanding the shank sleeve.
Expansible plugs of the above mentioned general type are known in the art. One such expansible plug is disclosed for example in the German document DE-A1 40 26 944. The expansible plug disclosed in this document has an expansible shank divided into two in the longitudinal direction and disc-shaped elements project inwards from both sections of the shank and overlap one another to form a closed expansible shank with a cylindrical outer surface. The disc-shaped expansible elements are provided with eccentrical bores with align coaxially when a fixing screw is screwed in to laterally displace the expansible elements. This process can be identified as an expansion process since the outer surface of the expansion region of the shank is consequently widened or expanded. Such an expansible plug has universal application and achieves high holding values not only in solid building materials but also in hollow building materials. The expansible elements arranged over a relatively long length of the expansible part provide a uniform expansion over the entire expansion region. When used in a hollow building material, the projecting disc-shaped expansible elements engage the cavities so that an interlocking engagement in the masonry is obtained in each bounding wall of a cavity.
When the expansible plug of the above mentioned type is used in solid building materials and in some cases also when it is used in hollow building materials, it may become braced slightly in a drilled hole after only a relatively short penetration depth. As a result it can snap off at the top end of the expansion region outside the drilled hole. Under unfavorable circumstances the expansible plug which already has been driven fully into a drilled hole can also rotate with a fixing screw as the fixing screw is being screwed in. As a result the screwing-in and the expansion of the expansible plug are rendered particularly difficult.